Method for generalized multi-protocol label switching routing to support wavelength switched optical network signal characteristics and network element compatibility constraints

ABSTRACT

An apparatus comprising a network element (NE) configured to support routing-associated signal compatibility constraint information that is associated with the NE using Generalized Multi-Protocol Label Switching (GMPLS) and an open shortest path first (OSPF) routing protocol, wherein the signal compatibility constraint information comprises a modulation type list, a Forward Error Correction (FEC) type list, a bit rate range list, and an acceptable client signal list, and wherein the signal compatibility constraint information is associated with a resource block (RB) pool for a plurality of NEs. Also disclosed is a network component comprising a transmitter unit configured to transmit signal compatibility constraints via GMPLS OSPF routing, wherein the signal compatibility constraints comprise a modulation type list, a FEC type list, a bit rate range list, and an acceptable client signal list.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/907,697 filed Oct. 19, 2010 by Young Lee et al. and entitled “Methodfor Generalized Multi-Protocol Label Switching Routing to SupportWavelength Switched Optical Network Signal Characteristics and NetworkElement Compatibility Constraints”, which claims priority to U.S.Provisional Patent Application No. 61/252,980 filed Oct. 19, 2009 byYoung Lee et al. and entitled “Method of GMPLS Routing to Support WSONSignal Characteristics and Network Element Compatibility Constraints,”both of which are incorporated herein by reference as if reproduced intheir entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

Wavelength division multiplexing (WDM) is one technology that isenvisioned to increase bandwidth capability and enable bi-directionalcommunications in optical networks. In WDM networks, multiple datasignals can be transmitted simultaneously between network elements (NEs)using a single fiber. Specifically, the individual signals may beassigned different transmission wavelengths so that they do notinterfere or collide with each other. The path that the signal takesthrough the network is referred to as the lightpath. One type of WDMnetwork, a wavelength switched optical network (WSON), seeks to switchthe optical signals with fewer optical-electrical-optical (OEO)conversions along the lightpath, e.g. at the individual NEs, thanexisting optical networks. One of the challenges in implementing WSONsis the determination of the routing and wavelength assignment (RWA) forthe various signals that are being transported through the network atany given time. To implement RWA, various NE related information can beforwarded from a Path Computation Client (PCC), such as a NE, andreceived and processed at a Path Computation Element (PCE).

SUMMARY

In one embodiment, the disclosure includes an apparatus comprising a NEconfigured to support routing-associated signal compatibility constraintinformation that is associated with the NE using GeneralizedMulti-Protocol Label Switching (GMPLS) and an open shortest path first(OSPF) routing protocol, wherein the signal compatibility constraintinformation comprises a modulation type list, a Forward Error Correction(FEC) type list, a bit rate range list, and an acceptable client signallist, and wherein the signal compatibility constraint information isassociated with a resource block (RB) pool for a plurality of NEs.

In another embodiment, the disclosure includes a network componentcomprising a transmitter unit configured to transmit signalcompatibility constraints via GMPLS OSPF routing, wherein the signalcompatibility constraints comprise a modulation type list, a FEC typelist, a bit rate range list, and an acceptable client signal list.

In yet another embodiment, the disclosure includes a method comprisingreceiving a plurality of signal compatibility constraints and signalcharacteristics for a NE in a WSON via GMPLS OSPF routing, wherein thesignal compatibility constraints comprise a modulation type list, a FECtype list, a bit rate range list, an acceptable client signal list, anda processing capability list.

These and other features will be more clearly understood from thefollowing detailed description taken in conjunction with theaccompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1 is a schematic diagram of an embodiment of a WSON system.

FIG. 2 is a schematic diagram of an embodiment of a combined RWAarchitecture.

FIG. 3 is a schematic diagram of an embodiment of a separated RWAarchitecture.

FIG. 4 is a schematic diagram of an embodiment of a distributedwavelength assignment architecture.

FIG. 5 is a protocol diagram of an embodiment of a PCC and PCEcommunication method.

FIG. 6 is a schematic diagram of an embodiment of a modulation type listheader.

FIG. 7 is a schematic diagram of an embodiment of a modulation type listType-Length-Value (TLV).

FIG. 8 is a schematic diagram of another embodiment of a modulation typelist TLV.

FIG. 9 is a schematic diagram of an embodiment of a FEC type list TLV.

FIG. 10 is a schematic diagram of another embodiment of a FEC type listTLV.

FIG. 11 is a schematic diagram of another embodiment of a FEC type listTLV.

FIG. 12 is a schematic diagram of an embodiment of a bit rate rangefield.

FIG. 13 is a schematic diagram of an embodiment of a bit rate range listTLV.

FIG. 14 is a schematic diagram of an embodiment of a processingcapability list TLV.

FIG. 15 is a schematic diagram of an embodiment of an additionalcapability parameter.

FIG. 16 is a schematic diagram of an embodiment of a client signal listTLV.

FIG. 17 is a schematic diagram of an embodiment of atransmitter/receiver unit.

FIG. 18 is a schematic diagram of an embodiment of a general-purposecomputer system.

DETAILED DESCRIPTION

It should be understood at the outset that although an illustrativeimplementation of one or more embodiments are provided below, thedisclosed systems and/or methods may be implemented using any quantityof techniques, whether currently known or in existence. The disclosureshould in no way be limited to the illustrative implementations,drawings, and techniques illustrated below, including the exemplarydesigns and implementations illustrated and described herein, but may bemodified within the scope of the appended claims along with their fullscope of equivalents.

GMPLS for WSON may support a plurality of types of wavelength switchingsystems. For hybrid electro-optical systems, such asoptical-electrical-optical (OEO) switches, regenerators, and/orwavelength converters, the GMPLS control plane may be restricted toprocessing WSON signals with specific characteristics or attributes. Insome cases, the WSON may comprise a limited quantity of NEs that may beconfigured to process one compatible class of signals. Suchimplementation may limit the WSON flexibility and prevent the efficientuse of some NEs, such as regenerators, OEO switches, and wavelengthconverters. In other cases, the processing capability of some NEs maynot be directly supported or used during signal routing. For example,performing a regeneration function on a signal may require provisioningduring the optical path establishment process.

Disclosed herein is a system and methods for extending the GMPLS controlplane to allow different signal types in WSONs or WDM networks, based ona plurality of signal compatibility constraints for a plurality of NEs.The system and methods include extending GMPLS routing mechanisms inhybrid electro-optical systems, where not all of the optical signals maybe compatible with all the NEs. The GMPLS OSPF routing protocol may beextended to support signal compatibility constraints associated with aplurality of different NEs, such as OEO switches, regenerators, and/orwavelength converters. Accordingly, a plurality of TLVs may be used toforward a plurality of NE signal compatibility constraints between theNEs. The NEs may also exchange other related information, such as aplurality of signal characteristics or attributes. The forwarded NEsignal compatibility constraints and signal attributes may be used aspart of the RWA information to establish paths between the NEs. The NEsignal compatibility constraints and the signal attributes may guaranteethat the calculated paths forward only signal types that are compatiblewith the NEs along the paths.

FIG. 1 illustrates one embodiment of a WSON system 100. The system 100may comprise a WSON 110, a control plane controller 120, and a PCE 130.The WSON 110, control plane controller 120, and PCE 130 may communicatewith each other via optical, electrical, or wireless means. The WSON 110may be any optical network that uses active or passive components totransport optical signals. For instance, the WSON 110 may be part of along haul network, a metropolitan network, or a residential accessnetwork. The WSON 110 may implement WDM to transport the optical signalsthrough the WSON 110, and may comprise various optical componentsincluding a plurality of NEs 112, which may be coupled to one anotherusing optical fibers. In an embodiment, the optical fibers may also beconsidered NEs 112. The optical signals may be transported through theWSON 110 over lightpaths that may pass through some of the NEs 112. Inaddition, some of the NEs 112, for example those at the ends of the WSON110, may be configured to convert between electrical signals fromexternal sources and the optical signals used in the WSON 110. Althoughfour NEs 112 are shown in the WSON 110, the WSON 110 may comprise anyquantity of NEs 112.

The NEs 112, also referred to as nodes, may be any devices or componentsthat transport signals through the WSON 110. In an embodiment, the NEs112 may consist essentially of optical processing components, such asline ports, add ports, drop ports, transmitters, receivers, amplifiers,optical taps, and so forth, and do not contain any electrical processingcomponents. Alternatively, the NEs 112 may comprise a combination ofoptical processing components and electrical processing components. Atleast some of the NEs 112 may be configured with wavelength converters,optical-electrical (OE) converters, electrical-optical (EO) converters,OEO converters, or combinations thereof. However, it may be advantageousfor at least some of the NEs 112 to lack such converters, as such mayreduce the cost and complexity of the WSON 110. In specific embodiments,the NEs 112 may comprise optical switches such as optical cross connects(OXCs), photonic cross connects (PXCs), type I or type II reconfigurableoptical add/drop multiplexers (ROADMs), wavelength selective switches(WSSs), fixed optical add/drop multiplexers (FOADMs), or combinationsthereof.

Some NEs 112 may be used for wavelength-based switching by forwarding,adding, or dropping any or all of the wavelengths that are used totransmit the optical signals. For instance, the NE 112 may comprise aplurality of ingress ports, such as line side ingress ports or addports, a plurality of egress ports, such as line side egress ports ordrop ports, or combinations thereof. The add ports and drop ports mayalso be called tributary ports. The optical signals handled by thesevarious ports may comprise one or a plurality of optical wavelengths.The line side ingress ports may receive the optical signals and sendsome or all of the optical signals to the line side egress ports, whichmay in turn transmit the optical signals. Alternatively, the line sideingress ports may redirect some or all of the optical signals to thedrop ports, which may drop the optical signals, for example, bytransmitting the optical signals outside the optical fibers. The addports may receive additional optical signals and send the opticalsignals to some of the line side egress ports, which may in turntransmit the optical signals.

In some instances, the NE 112 may comprise at least one colored portthat may be an ingress port or an egress port, which may receive ortransmit, respectively, the optical signal at a fixed optical wavelengthor a limited range of optical wavelengths, e.g. less then a full rangeof wavelengths as defined by a standard, such as the course WDM (CWDM)or dense WDM (DWDM) standards, which are discussed below. Additionallyor alternatively, the NE may comprise at least one colorless port thatmay be an ingress port or an egress port, which may receive or transmit,respectively, the optical signal at any one of a plurality of differentwavelengths, e.g. a full range of wavelengths as defined by a standard,such as CWDM or DWDM. The NE 112 that comprises a colorless port andsupports any or a plurality of variable wavelengths may be referred toas a colorless NE. Alternatively, the NE 112 that does not comprise acolorless port and supports one or a plurality of predetermined (orspecified) wavelengths may be referred to as a colored NE. Further, theNE 112 may comprise one or a plurality of wavelength converters (WCs)that may convert one or a plurality of wavelengths between at least oneingress port and one egress port. For instance, a WC may be positionedbetween an ingress port and an egress port and may be configured toconvert a first wavelength received at the ingress port into a secondwavelength, which may then be transmitted at the egress port. The WC maycomprise any quantity of optical and/or electrical components that maybe configured for wavelength conversion, such as an OEO converter and/ora laser.

The NEs 112 may be coupled to each other via optical fibers, alsoreferred to as links. The optical fibers may be used to establishoptical links and transport the optical signals between the NEs 112. Theoptical fibers may comprise standard single mode fibers (SMFs) asdefined in International Telecommunication Union (ITU) TelecommunicationStandardization Sector (ITU-T) standard G.652, dispersion shifted SMFsas defined in ITU-T standard G.653, cut-off shifted SMFs as defined inITU-T standard G.654, non-zero dispersion shifted SMFs as defined inITU-T standard G.655, wideband non-zero dispersion shifted SMFs asdefined in ITU-T standard G.656, or combinations thereof. All of theITU-T standards above are incorporated herein by reference. These fibertypes may be differentiated by their optical impairment characteristics,such as attenuation, chromatic dispersion, polarization mode dispersion,four wave mixing, or combinations thereof. These effects may bedependent upon wavelength, channel spacing, input power level, orcombinations thereof. The optical fibers may be used to transport WDMsignals, such as CWDM signals as defined in ITU-T G.694.2 or DWDMsignals as defined in ITU-T G.694.1. All of the standards described inthis disclosure are incorporated herein by reference.

The control plane controller 120 may coordinate activities within theWSON 110. Specifically, the control plane controller 120 may receiveoptical connection requests and provide lightpath signaling to the WSON110 via an Interior Gateway Protocol (IGP) such as GMPLS, therebycoordinating the NEs 112 such that data signals are routed through theWSON 110 with little or no contention. In addition, the control planecontroller 120 may communicate with the PCE 130 using PCE protocol(PCEP) to provide the PCE 130 with information that may be used for theRWA, receive the RWA from the PCE 130, and/or forward the RWA to the NEs112. The control plane controller 120 may be located in a componentoutside of the WSON 110, such as an external server, or may be locatedin a component within the WSON 110, such as a NE 112.

The PCE 130 may perform all or part of the RWA for the WSON system 100.Specifically, the PCE 130 may receive wavelength and/or otherinformation that may be used for the RWA from the control planecontroller 120, from the WSON 110, or both. The wavelength informationmay comprise port wavelength restrictions for the NE 112, such as for acolored NE that comprises a colored port. The PCE 130 may process theinformation to obtain the RWA, for example, by computing the routes,e.g. lightpaths, for the optical signals, specifying the opticalwavelengths that are used for each lightpath, and determining the NEs112 along the lightpath at which the optical signal should be convertedto an electrical signal or a different wavelength. The RWA data mayinclude at least one route for each incoming signal and at least onewavelength associated with each route. The PCE 130 may then send all orpart of the RWA data to the control plane controller 120 or directly tothe NEs 112. To assist the PCE 130 in this process, the PCE 130 maycomprise a global traffic-engineering database (TED), a RWA informationdatabase, an optical performance monitor (OPM), a physical layerconstraint (PLC) information database, or combinations thereof. The PCE130 may be located in a component outside of the WSON 110, such as anexternal server, or may be located in a component within the WSON 110,such as a NE 112.

In some embodiments, the RWA information may be sent to the PCE 130 by aPCC. The PCC may be any client application requesting a path computationto be performed by the PCE 130. The PCC may also be any networkcomponent that makes such a request, such as the control planecontroller 120, or any NE 112, such as a ROADM or a FOADM.

FIG. 2 illustrates an embodiment of a combined RWA architecture 200. Inthe combined RWA architecture 200, the PCC 210 communicates the RWArequest and the required information to the PCE 220, which implementsboth the routing assignment and the wavelength assignment functionsusing a single computation entity, such as a processor. For example, theprocessor may process the RWA information using a single or multiplealgorithms to compute the lightpaths as well as to assign the opticalwavelengths for each lightpath. The amount of RWA information needed bythe PCE 220 to compute the RWA may vary depending on the algorithm used.If desired, the PCE 220 may not compute the RWA until sufficient networklinks are established between the NEs or when sufficient RWA informationregarding the NEs and the network topology is provided. The combined RWAarchitecture 200 may be preferable for network optimization, smallerWSONs, or both.

FIG. 3 illustrates an embodiment of a separated RWA architecture 300. Inthe separated RWA architecture 300, the PCC 310 communicates the RWArequest and the required information to the PCE 320, which implementsboth the routing function and the wavelength assignment function usingseparate computation entities, such as processors 322 and 324.Alternatively, the separated RWA architecture 300 may comprise twoseparate PCEs 320 each comprising one of the processors 322 and 324.Implementing routing assignment and wavelength assignment separately mayoffload some of the computational burden on the processors 322 and 324and reduce the processing time. In an embodiment, the PCC 310 may beaware of the presence of only one of two processors 322, 324 (or twoPCEs) and may only communicate with that processor 322, 324 (or PCE).For example, the PCC 310 may send the RWA information to the processor322, which may compute the lightpath routes and forward the routingassignment to the processor 324 where the wavelength assignments areperformed. The RWA may then be passed back to the processor 322 and thento the PCC 310. Such an embodiment may also be reversed such that thePCC 310 communicates with the processor 324 instead of the processor322.

In either architecture 200 or 300, the PCC 210 or 310 may receive aroute from the source to destination along with the wavelengths, e.g.GMPLS labels, to be used along portions of the path. The GMPLS signalingsupports an explicit route object (ERO). Within an ERO, an ERO labelsub-object can be used to indicate the wavelength to be used at aparticular NE. In cases where the local label map approach is used, thelabel sub-object entry in the ERO may have to be translated.

FIG. 4 illustrates a distributed wavelength assignment architecture 400.In the distributed wavelength assignment architecture 400, the PCE 410may receive some or all of the RWA information from the NEs 420, 430,and 440, perhaps via direct link, and implements the routing assignment.The PCE 410 then directly or indirectly passes the routing assignment tothe individual NEs 420, 430, and 440, which assign the wavelengths atthe local links between the NEs 420, 430, and 440 based on localinformation. Specifically, the NE 420 may receive local RWA informationfrom the NEs 430 and 440 and send some or all of the RWA information tothe PCE 410. The PCE 410 may compute the lightpaths using the receivedRWA information and send the list of lightpaths to the NE 420. The NE420 may use the list of lightpaths to identify the NE 430 as the next NEin the lightpath. The NE 420 may establish a link to the NE 430 and usethe received local RWA information that may comprise additionalconstraints to assign a wavelength for transmission over the link. TheNE 430 may receive the list of lightpaths from the NE 420, use the listof lightpaths to identify the NE 440 as the next NE in the lightpath,establish a link to the NE 440, and assign the same or a differentwavelength for transmission over the link. Thus, the signals may berouted and the wavelengths may be assigned in a distributed mannerbetween the remaining NEs in the network. Assigning the wavelengths atthe individual NEs may reduce the amount of RWA information that has tobe sent to the PCE 410.

FIG. 5 illustrates an embodiment of a communication method 500 betweenthe PCC and the PCE. In the method 500, the PCC sends a message 502 tothe PCE, where the message 502 comprises at least some of the RWAinformation described below. The message 502 may also contain a statusindicator that indicates whether the RWA information is static ordynamic. In an embodiment, the status indicator may indicate how longthe static or dynamic status lasts so that the PCE can know how long theRWA information is valid and/or when to expect an update. Additionallyor alternatively, the message 502 may contain a type indicator thatindicates whether the RWA information is associated with a node that maycomprise a NE, a link, such as a WDM link, or both. In some instances,an acknowledgement message that confirms receipt of the message 502 maybe sent from the PCE to the PCC, e.g. subsequent to receipt of themessage 502.

The method 500 may be implemented using any suitable protocol, such asthe IGP. The IGP may be a routing protocol used for exchanging routeinformation among gateways, such as a host computer or routers, in anautonomous network. Internet networks can be divided into multipledomains or multiple autonomous systems, where one domain congregates abatch of host computers and routers that employ the same routingprotocol. In such a case, the IGP may be provided for selecting routesin a domain. The IGP may be link-state routing protocol in that eachnode possesses information regarding the complete network topology. Insuch a case, each node can independently calculate the best next hopfrom it for every possible destination in the network using localinformation of the topology. The collection of best next hops may formthe routing table for the node. In a link-state protocol, the onlyinformation that may be passed between the nodes is information used toconstruct the connectivity maps. Examples of suitable IGPs includeGMPLS, OSPF, and intermediate system to intermediate system (IS-IS).

As mentioned above, the message 502 may comprise RWA information thatmay be exchanged between the PCC and the PCE. The RWA information mayalso be exchanged, e.g. via signaling, between any of the NEs and/orbetween the NEs and the PCE. The exchanged RWA information may comprisea plurality of signal attributes or characteristics that may define orcharacterize a plurality of WSON signals. The signal compatibilityconstraints information may also include a plurality of NE signalcompatibility constraints, such as regarding the different signalattributes or characteristics. The NE signal compatibility constraintsmay be transported, e.g. between the NEs, and used, e.g. by the PCE, todetermine the different signals that may be processed by the differentNEs and calculate suitable paths to transfer compatible signals betweenthe NEs.

The NE signal compatibility constraints may indicate whether the NE iscompatible with WSON signals, for instance based on a limited wavelengthrange, a modulation type restriction (e.g. including FEC coding), a bitrate range restriction, a client signal dependence, or combinationsthereof. In an embodiment, the NE signal compatibility constraintsinformation may comprise a modulation type list, a FEC type list, a bitrate range list, and/or an acceptable client signal list. Suchinformation may be routed in GMPLS, for instance using the OSPF protocoland may be associated with one NE or multiple NEs, such as in a resourceblock (RB) pool. The information may be routed using a plurality ofcorresponding TLVs or fields, which may be sent in Record Route Objects(RROs) and/or EROs between the NEs.

The modulation type list, also referred to herein as optical tributarysignal class, may comprise at least one of an ITU-T standardizedmodulation type, a vendor specific modulation type, or both. The ITU-Tstandardized modulation type(s) and/or the vendor specific modulationtype(s) may be handled or processed by a NE or a RB pool. For instance,the modulation type list may be represented as:

<modulation-list>::=[<STANDARD-MODULATION>|<VENDOR-MODULATION>] . . . ,

where STANDARD-MODULATION is an object that indicates an ITU-Tstandardized optical tributary signal class and VENDOR-MODULATION is anobject that indicates a vendor specific modulation type. Themodulation-list may comprise any quantity of STANDARD-MODULATION and/orVENDOR-MODULATION objects.

The FEC type list may comprise one or a plurality of FEC types that maybe handled or processed by a NE or a RB pool. The FEC type list may berepresented as:

-   -   <fec-list>::=[<FEC>] . . . ,        where FEC is an object that indicates an ITU-T standardized FEC        type as defined in standard G.709 or standard G.707, both of        which are incorporated herein by reference, or a vendor specific        FEC type. The fec-list may comprise any quantity of FEC objects.

The bit rate range list may comprise one or a plurality of bit rateranges that may be handled or processed by a NE or a RB pool. The bitrate range list may be represented as:

-   -   <rate-range-list>::=[<rate-range>] . . . ,        where rate-range is an object that indicates a range of        supported bit rate. The rate-range-list may comprise any        quantity of rate-range objects, which may be each represented        as:    -   <rate-range>::=[<START-RATE><END-RATE>],        where START-RATE is an object that indicates a range start and        END-RATE is an object that indicates a range end.

The acceptable client signal list may comprise one or a plurality ofsignal identifiers that indicate the signals that may be handled orprocessed by a NE or a RB pool. The acceptable client signal list may berepresented as:

-   -   <client-signal-list>::=[<GPID>] . . . ,        where General Protocol Identifier (GPID) is an object that        indicates an Internet Engineering Task Force (IETF) standardized        GPID value as defined in Request for Comments (RFC) 3471 or RFC        4328, both of which are incorporated herein by reference. The        client-signal-list may comprise any quantity of GPID objects.

The IETF RFC 4202, which is incorporated herein by reference, introducesInterface Switching Capability Descriptors (ISCDs) to extend GMPLSrouting. For instance, the IETF RFC 4202 describes a Lambda-SwitchCapable (LSC) descriptor for routing any additional information inGMPLS. The IETF RFC 4202 and RFC 5307, both of which are incorporatedherein by reference, also define a plurality of TLVs for ISCDs,including a Switching Capability-specific information TLV or sub-TLV.However, none of the RFCs specifies any of the NE signal compatibilityconstraints information described above. In an embodiment, GMPLSrouting, for instance based on OSPF, may be extended using a pluralityof TLVs and/or LSC ISCDs that comprise the NE signal compatibilityconstraints described above.

FIG. 6 illustrates one embodiment of a modulation type list header 600in a modulation type list TLV that may be forwarded between the NEs viaGMPLS or OSPF routing. The modulation type list header 600 may comprisea standardized modulation (S) bit 602, an input modulation format (I)bit 604, a modulation identifier (ID) 606, and a length field 608. In anembodiment, the modulation type list header 600 may have a size of about32 bits. The S bit 602 may be set, e.g. to about one, to indicate astandardized modulation format or may be set, e.g. comprise about zero,to indicate a vendor specific modulation format. The I bit 604 may beset, e.g. to about one, to indicate an input modulation format and/or asink modulation type or may not be set, e.g. to about zero, to indicatean output modulation format and/or a source modulation type. Themodulation ID 606 may comprise a unique ID associated with onemodulation format/type. The length field 608 may indicate the entiresize of the modulation type list TLV.

FIG. 7 illustrates one embodiment of a modulation type list TLV 700,which may include the modulation type list header 600. The modulationtype list TLV 700 may comprise an S bit 702, an I bit 704, a modulationID 706, and a length field 708, which may be similar to thecorresponding fields in modulation type list header 600. The modulationtype list TLV 700 may also comprise at least one field 710 than includesadditional modulation parameters based on the modulation ID 706.Specifically, the modulation type list TLV 700 may correspond to astandardized modulation format. As such, the S bit 702 may be set, e.g.to about one. The modulation ID 706 may comprise a value of about one toindicate an optical tributary signal class non-return to zero (NRZ) 1.25gigabits per second (G), a value of about two to indicate an opticaltributary signal class NRZ 2.5 G, a value of about three to indicate anoptical tributary signal class NRZ 10 G, a value of about four toindicate an optical tributary signal class NRZ 40 G, or a value of aboutfive to indicate an optical tributary signal class return to zero (RZ)40 G. Alternatively, the modulation ID 706 may comprise a reserved valueof about zero. The field 710 may indicate allowable modulation types inthe source (transmitter) and/or the sink (receiver).

FIG. 8 illustrates another embodiment of a modulation type list TLV 800,which may include the modulation type list header 600. The modulationtype list TLV 800 may comprise an S bit 802, an I bit 804, and a lengthfield 808, which may be similar to the corresponding fields inmodulation type list header 600. The modulation type list TLV 800 mayalso comprise a vendor modulation ID 806, an enterprise number 810, andat least one field 812 that includes vendor specific additionalmodulation parameters. Specifically, the modulation type list TLV 800may correspond to vendor specific modulation format. As such, the S bit802 may be set, e.g. to about zero. The vendor modulation ID 806 maycomprise an assigned ID for the modulation type, e.g. for a vendor. Theenterprise number 810 may comprise a unique identifier of anorganization and may comprise about 32 bits. The enterprise numbers maybe assigned by the Internet Assigned Numbers Authority (IANA) andmanaged through IANA registry, e.g. according to RFC 2578, which isincorporated herein by reference. The field 812 may comprise additionalparameters that characterize vendor specific modulation.

FIG. 9 illustrates one embodiment of a FEC type list TLV 900 that may beforwarded between the NEs via GMPLS or OSPF routing. The FEC type listTLV 900 may comprise an S bit 902, an input FEC format (I) bit 904, aFEC ID 906, a length field 908, and at least one field 910 that includesadditional FEC parameters based on the FEC ID 906. The S bit 902 may beset, e.g. to about one, to indicate a standardized FEC format or may beset, e.g. comprise about zero, to indicate a vendor specific FEC format.The I bit 904 may be set, e.g. to about one, to indicate an input FECformat and/or a sink FEC type or may not be set, e.g. to about zero, toindicate an output FEC format and/or a source FEC type. The FEC ID 906may comprise a unique ID associated with one FEC format/type. The lengthfield 908 may indicate the entire size of the FEC type list TLV 900.

FIG. 10 illustrates another embodiment of a FEC type list TLV 1000 thatmay be forwarded between the NEs via GMPLS or OSPF routing. The FEC typelist TLV 1000 may comprise an S bit 1002, an I bit 1004, and a lengthfield 1008, which may be similar to the corresponding components of theFEC type list TLV 900. The FEC type list TLV 1000 may also comprise aFEC ID 1006 and at least one field 1010 that includes additional FECparameters based on the FEC ID 1006. Specifically, the FEC type listheader 1000 may correspond to a standardized FEC format. As such, the Sbit 1002 may be set, e.g. to about one. The FEC ID 1006 may comprise avalue of about one to indicate an ITU-T G.709 Reed-Solomon FEC or avalue of about two to indicate an ITU-T G.907V compliant Ultra FEC. TheFEC 1006 may comprise a value of about three to indicate an ITU-TG.975.1 Concatenated FEC (RS(255,239)/CSOC(n0/k0=7/6,j=8)), a value ofabout four to indicate a G.975.1 Concatenated FEC(Bose-Chaudhuri-Hocquengham or BCH(3860,3824)/BCH(2040,1930)), a valueof about five to indicate a G.975.1 Concatenated FEC(RS(1023,1007)/BCH(2407,1952)), or a value of about six to indicate aG.975.1 Concatenated FEC (RS(1901,1855)/Extended Hamming Product Code(512,502)×(510,500)). The FEC 1006 may comprise a value of about sevento indicate a G.975.1 low density parity check (LDPC) Code, a value ofabout eight to indicate a G.975.1 Concatenated FEC (Two orthogonallyconcatenated BCH codes), a value of about nine to indicate a G.975.1RS(2720,2550), or a value of about 10 to indicate a G.975.1 ConcatenatedFEC (Two interleaved extended BCH(1020,988) codes). The standards G.709Vand G.975.1 are both incorporated herein by reference. Alternatively,the FEC ID 1006 may comprise a reserved value of about zero. The field1010 may indicate allowable FEC types in the source (transmitter) and/orthe sink (receiver).

FIG. 11 illustrates another embodiment of a FEC type list TLV 1100 thatmay be forwarded between the NEs via GMPLS or OSPF routing. The FEC typelist TLV 1100 may comprise an S bit 1102, an I bit 1104, and a lengthfield 1108, which may be similar to the corresponding components of theFEC type list TLV 900. The FEC type list TLV 1100 may also comprise avendor FEC ID 1106, an enterprise number 1110, and at least one field1112 that includes vendor specific additional FEC parameters.Specifically, the FEC type list TLV 1100 may correspond to vendorspecific FEC format. As such, the S bit 1102 may be set, e.g. to aboutzero. The vendor FEC ID 1106 may comprise a vendor assigned ID for theFEC type. The enterprise number 1110 may comprise a unique identifier ofan organization and may comprise about 32 bits. The enterprise numbersmay be assigned by IANA and managed through IANA registry, e.g.according to RFC 2578. The field 1112 may comprise additional parametersthat characterize vendor specific FEC.

FIG. 12 illustrates one embodiment of a bit rate range field 1200 in abit rate range list TLV that may be forwarded between the NEs via GMPLSor OSPF routing. The bit rate range field 1200 may comprise a startingbit rate 1202 and an ending bit rate 1204. The starting bit rate 1202and the ending bit rate 1204 may indicate the starting bit rate andending bit rate, e.g. in bits per second, in a bit rate range that maybe supported by a NE. The starting bit rate 1202 and the ending bit rate1204 may each comprise about 32 bit Institute of Electrical andElectronics Engineers (IEEE) floating point numbers. Further, thestarting bit rate 1204 may comprise a smaller number than the ending bitrate 1204.

FIG. 13 illustrates one embodiment of a bit rate range list TLV 1300,which may comprise at least on bit range field 1302. Each bit rangefield 1302 may be substantially similar to the bit rate range field 1200and may indicate a different bit rate range that may be supported by theNE. For instance, each bit range field 1302 may indicate a differentstarting bit rate and a different ending bit rate. The different bitrate ranges indicated in the bit rate range list TLV 1300 may or may notoverlap.

FIG. 14 illustrates one embodiment of a processing capability list TLV1400 that may be forwarded between the NEs via GMPLS or OSPF routing.The processing capability list TLV 1400 may comprise a processingcapability (Cap) ID 1402, a length field 1404, and at least one field1406 that includes additional capability parameters based on theprocessing capability ID 1402. The processing capability ID 1402 maycomprise a unique ID associated with one processing capability for a NE.For instance, the processing capability ID 1402 may indicate one of aregeneration capability, a fault and performance monitoring, or other NEprocessing capability. The length field 1404 may indicate the entiresize of the processing capability list TLV 1400. The field 1406 maycomprise at least one additional capability parameter, as describedbelow.

FIG. 15 illustrates one embodiment of an additional capability parameter1500 that may be included in the processing capability list TLV 1400,e.g. in the field 1406. The additional capability parameter 1500 mayindicate additional processing capability information that may beassociated with the processing capability ID 1402. For instance, theprocessing capability parameter 1500 may be added to the processingcapability list TLV 1400 if the processing capability ID 1402 indicatesa regeneration capability. The additional capability parameter 1500 maycomprise a type (T) field 1502, a capability (C) field 1504, and areserved field 1506. The T field 1502 may indicate the regenerator typeof the associated NE. The T field 1502 may comprise a value of about oneto indicate a 1R regenerator type, a value of about two to indicate a 2Rregenerator type, a value of about three to indicate a 3R regeneratortype, or a value of about four to indicate a 4R regenerator type.Alternatively, the T field 1502 may comprise a reserved value of aboutzero.

The C field 1504 may indicate the capability of the associatedregenerator or NE. The C field 1504 may comprise a value of about one toindicate a fixed regeneration point or a value of about two to indicatea selective regeneration pool(s). In the case of selective regenerationpool(s), regeneration pool properties such as ingress and/or egressrestriction and availability information may be needed. Such informationmay be provided in other TLVs. Alternatively, the C field 1504 maycomprise a reserved value of about zero. The reserved field 1506 may bereserved and may not be used.

FIG. 16 illustrates one embodiment of a client signal list TLV 1600 thatmay be forwarded between the NEs via GMPLS or OSPF routing. The clientsignal list TLV 1600 may comprise a number of GPIDs 1602 and at leastone GPID 1604. The number of GPIDs 1602 may specify the quantity ofGPIDs 1604 included in the client signal list TLV 1600 and each GPID1604 may comprise an integer greater or equal to about one. Each GPID1604 may indicate a specific client signal format, which may be assignedby IANA, such as specified in RFC 3471 and RFC 4328.

FIG. 17 illustrates an embodiment of a transmitter/receiver unit 1700,which may be located at or coupled to any of the NEs in the WSON. Thetransmitter/receiver unit 1700 may be any device that transports framesthrough the WSON. For instance, the transmitter/receiver unit 1700 maycorrespond to or may be located in a network node, which may comprise aregenerator, an OEO switch, a wavelength converter, an OXC, a PXC, atype I or type II ROADM, a WSS, a FOADM, or combinations thereof. Thenode may include bridges, switches, routers, or various combinations ofsuch devices. The transmitted/receiver unit 1700 may comprise aplurality of ingress ports or units 1710 for receiving frames, objects,or TLVs from other nodes, logic circuitry 1720 to determine which nodesto send the frames to, and a plurality of egress ports or units 1730 fortransmitting frames to the other nodes.

The network components described above may be implemented on anygeneral-purpose network component, such as a computer or networkcomponent with sufficient processing power, memory resources, andnetwork throughput capability to handle the necessary workload placedupon it. FIG. 18 illustrates a typical, general-purpose networkcomponent 1800 suitable for implementing one or more embodiments of thecomponents disclosed herein. The network component 1800 includes aprocessor 1802 (which may be referred to as a central processor unit orCPU) that is in communication with memory devices including secondarystorage 1804, read only memory (ROM) 1806, random access memory (RAM)1808, input/output (I/O) devices 1810, and network connectivity devices1812. The processor 1802 may be implemented as one or more CPU chips, ormay be part of one or more application specific integrated circuits(ASICs).

The secondary storage 1804 is typically comprised of one or more diskdrives or tape drives and is used for non-volatile storage of data andas an over-flow data storage device if RAM 1808 is not large enough tohold all working data. Secondary storage 1804 may be used to storeprograms that are loaded into RAM 1808 when such programs are selectedfor execution. The ROM 1806 is used to store instructions and perhapsdata that are read during program execution. ROM 1806 is a non-volatilememory device that typically has a small memory capacity relative to thelarger memory capacity of secondary storage. The RAM 1808 is used tostore volatile data and perhaps to store instructions. Access to bothROM 1806 and RAM 1808 is typically faster than to secondary storage1804.

At least one embodiment is disclosed and variations, combinations,and/or modifications of the embodiment(s) and/or features of theembodiment(s) made by a person having ordinary skill in the art arewithin the scope of the disclosure. Alternative embodiments that resultfrom combining, integrating, and/or omitting features of theembodiment(s) are also within the scope of the disclosure. Wherenumerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (e.g. from about 1 to about 10 includes 2, 3, 4,etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example,whenever a numerical range with a lower limit, R₁, and an upper limit,R_(u), is disclosed, any number falling within the range is specificallydisclosed. In particular, the following numbers within the range arespecifically disclosed: R=R₁+k*(R_(u)−R₁), wherein k is a variableranging from 1 percent to 100 percent with a 1 percent increment, i.e.,k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . , 50percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97percent, 98 percent, 99 percent, or 100 percent. Moreover, any numericalrange defined by two R numbers as defined in the above is alsospecifically disclosed. Use of the term “optionally” with respect to anyelement of a claim means that the element is required, or alternatively,the element is not required, both alternatives being within the scope ofthe claim. Use of broader terms such as comprises, includes, and havingshould be understood to provide support for narrower terms such asconsisting of, consisting essentially of, and comprised substantiallyof. Accordingly, the scope of protection is not limited by thedescription set out above but is defined by the claims that follow, thatscope including all equivalents of the subject matter of the claims.Each and every claim is incorporated as further disclosure into thespecification and the claims are embodiment(s) of the presentdisclosure. The discussion of a reference in the disclosure is not anadmission that it is prior art, especially any reference that has apublication date after the priority date of this application. Thedisclosure of all patents, patent applications, and publications citedin the disclosure are hereby incorporated by reference, to the extentthat they provide exemplary, procedural, or other details supplementaryto the disclosure.

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods might beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and could be made without departing from the spirit and scopedisclosed herein.

What is claimed is:
 1. A method comprising: receiving an Open ShortestPath First (OSPF) link-state message from an optical node that describesthe node, wherein the optical node is a wavelength switched opticalnetwork (WSON) network element, wherein the message comprises resourceblock information including signal compatibility constraints of thenode, and wherein the signal compatibility constraints indicate limitsof the node for processing specified types of optical signals.
 2. Themethod of claim 1, wherein the resource block information comprises anacceptable client signal list containing a list of input client signaltypes acceptable to the node.
 3. The method of claim 2, wherein theacceptable client signal list comprises a list of General ProtocolIdentifiers (GPIDs).
 4. The method of claim 3, wherein the acceptableclient signal list comprises: a number of GPIDs field that indicates anumber of GPIDs included in the acceptable client signal list; and atleast one GPID field that comprises the GPIDS.
 5. The method of claim 1,wherein the resource block information comprises a processingcapabilities list that contains a list of resource processingcapabilities of the node.
 6. The method of claim 5, wherein theprocessing capabilities list indicates a regeneration capability, afault and performance monitoring capability, a vendor specificcapability, or combinations thereof.
 7. The method of claim 5, whereinthe processing capabilities list comprises: a Processing CapabilitiesIdentifier (ID) field that indicates a type of processing capability;and an Additional capability parameters depending upon processing IDfield that indicates additional capability parameters based onprocessing capability type.
 8. The method of claim 7, wherein theProcessing Capabilities ID field indicates a regeneration capability. 9.The method of claim 8, wherein the additional capability parameterscomprise: a Type (T) field that indicates a type of regenerator; aCapability (C) field that indicates a capability of the regenerator; anda reserved field.
 10. The method of claim 9, wherein the T field is setto a value of zero to indicate a reserved value, a value of one toindicate a 1R regenerator, a value of two to indicate a 2R regenerator,a value of three to indicate a 3R regenerator, or combinations thereof.11. The method of claim 9, wherein the C field is set to a value of zeroto indicate a reserved value, a value of one to indicate a fixedregeneration point, a value of two to indicate a selective regenerationpoint, or combinations thereof.
 12. The method of claim 1, wherein theresource block information comprises relatively static information aboutthe resource block.
 13. The method of claim 1, wherein the messagefurther comprises resource wavelength constraints that describe alimited wavelength range of the node.
 14. A method comprising: receivingan Open Shortest Path First (OSPF) link-state message from an opticalnode that describes the node, wherein the optical node is a wavelengthswitched optical network (WSON) network element, wherein the messagecomprises resource block information including compatibility constraintsof the node, wherein the resource block information comprises aprocessing capabilities list that contains a list of resource processingcapabilities of the node, and wherein the processing capabilities listcomprises: a Processing Capabilities Identifier (ID) field thatindicates a type of processing capability; a Length field that indicatesa length of the processing capabilities list; and an Additionalcapability parameters depending upon processing ID field that indicatesadditional capability parameters based on processing capability type.15. The method of claim 14, wherein the Processing Capabilities ID fieldindicates a regeneration capability.
 16. The method of claim 15, whereinthe additional capability parameters comprise: a Type (T) field thatindicates a type of regenerator; a Capability (C) field that indicates acapability of the regenerator; and a reserved field.
 17. The method ofclaim 16, wherein the T field is set to a value of one to indicate a 1Rregenerator, a value of two to indicate a 2R regenerator, a value ofthree to indicate a 3R regenerator, or combinations thereof.
 18. Themethod of claim 16, wherein the C field is set to a value of zero toindicate a reserved value, a value of one to indicate a fixedregeneration point, a value of two to indicate a selective regenerationpoint, or combinations thereof.
 19. An optical node comprising: amemory; and a processor coupled to the memory and configured to causethe optical node to transmit an Open Shortest Path First (OSPF)link-state message that describes the node, wherein the optical node isa wavelength switched optical network (WSON) network element, whereinthe message comprises resource block information including compatibilityconstraints of the node, wherein the resource block informationcomprises a processing capabilities list that contains a list ofresource processing capabilities of the node, and wherein the processingcapabilities list comprises: a Processing Capabilities Identifier (ID)field that indicates a type of processing capability; a Length fieldthat indicates the length of the processing capabilities list; and anAdditional capability parameters depending upon processing ID field thatindicates additional capability parameters based on processingcapability type.
 20. The optical node of claim 19, wherein the resourceblock information comprises an input-acceptable client signal listcontaining a list of input client signal types acceptable to the node,and wherein the acceptable input client signal list comprises: a numberof General Protocol Identifiers (GPIDs) field that indicates a number ofGPIDs included in the acceptable input client signal list; and at leastone GPID field that comprises the GPIDS.
 21. The optical node of claim19, wherein the processing capabilities list indicates a regenerationcapability, a fault and performance monitoring capability, a vendorspecific capability, or combinations thereof.
 22. The optical node ofclaim 19, wherein the Processing Capabilities ID indicates aregeneration capability, and wherein the additional capabilityparameters comprise: a Type (T) field that indicates a type ofregenerator; a Capability (C) field that indicates a capability of theregenerator; and a reserved field.
 23. The optical node of claim 22,wherein the T field is set to a value of one to indicate a 1Rregenerator, a value of two to indicate a 2R regenerator, a value ofthree to indicate a 3R regenerator, or combinations thereof, and whereinthe C field is set to a value of zero to indicate a reserved value, avalue of one to indicate a fixed regeneration point, a value of two toindicate a selective regeneration point, or combinations thereof.